Sunday, December 1, 2019

Interstellar

In the movie Interstellar, it was correctly shown how time dilation caused life on earth to flow much faster(decades) than compared to cooper who had only passed a few years by. I love that they were accurate about the physics of relativity in the movie because it makes it more interesting to watch. But there is one concept from the movie that I am wondering about. When Cooper went into the black hole and came back out, it seems that not too much time had passed compared to before. I also wonder, shouldn’t Cooper had come out to find the whole universe passed by, or at least his daughter Murphy and even Dr. Brand dead? I guess no one knows if time stops completely once you pass the event horizon. I do find this subject so interesting. Just thinking about how time and space are one blows my mind.

Also in the movie, Cooper should have been dead by the time he reached the accretion disk because it would’ve been incredibly hot. Once he was just close enough, he along with his spaceship should’ve gotten ripped apart, or spaghettified. Spaghettification happens when gravity pulls harder on the side closest to the black hole than on the further side. If you were falling in a black hole feet first, gravity at your feet would be much stronger than the gravity at your head, so you would get pulled and stretched apart molecule by molecule. 

Image result for spaghettification

Overall I think this is a really great movie and I very much enjoy watching it over and over. Movies like this are cool because it, at least for me, really sparks my curiosity. I just think about why some things are. 

Saturday, November 16, 2019

Contact and Time Dilation

In many spacey movies, you sometimes find that people will travel at the speed of light, and come back to earth to find people much older, or even dead, whereas the person traveling hadn’t aged at all. In the movie Contact, another one of my many favorites, an astronomer named Ellie travels through a wormhole, seemingly traveling at the speed of light, or close to it. Ellie traveled for 18 hours, but when she came back, everyone never saw Ellie go anywhere, or so it seemed. The problem with this situation is that it should've been vice versa. Ellie should’ve felt like she was gone for a few seconds, and everyone else should’ve seen Ellie go bye bye for 18 hours, or even days and years. Here is a fact: time runs slower in inertial reference frames, where there is no acceleration. Where a clock may tick twice every two seconds in a state of rest, where there is no acceleration, a clock may tick once every two seconds in an inertial reference frame. The person traveling at high speed would see the observer of them moving faster than them because their time would be running slower. Though it wouldn’t make sense that you could observe someone at rest, while you are moving near the speed of light, you would theoretically see them moving faster, while you felt the same, and they would see you moving and living slower while they felt the same.  This is called time dilation, a crazy, but super cool concept.

Thursday, November 14, 2019

Flight of the Navigator

Image result for flight of the navigator

Flight of the Navigator is an older movie(1978) that many young people have never seen. However, this is a movie I grew up watching. Until recently, I have never paid attention to movie physics. In Flight of the Navigator, a boy named David meets a computer being named Max who is also the spaceship. In the movie, there are numerous flights in which David speeds up and stops almost instantly. David even goes on to fly more than 500 light years in a couple of hours, eventually coming home to his family 10 years older.

There is a particular scene in the movie where David flies up above the earth in about 5.5 seconds, and comes back down in the same amount of time. Here is the scene:

I have estimated that the distance he traveled was about 321km. In the scene, David says to take him 20 miles away, but Max the spaceship takes him much further. Using distance/time, I found that he is moving at about 58.4km/second. This is very, very fast, in fact faster than the ISS’s orbit speed! Standing on the earth you experience one g, but in his flight he would experience 5,960 g’s of force. I converted 58.4km/second into meters/second, and then divided the number by 9.8meters/second squared to find the g's he would experience. With no suits or equipment, people tend to black out at about 5-6 g’s. When David arrives in space, he is well awake and yelling to go back down to earth, where realistically, he should probably be dead because his blood would rush away from his brain while going up, and vice versa going back down. This is a violation of human limits. In the scene, when David is flying upwards, he does experience some force. His speech is slurred and his arms are stuck to the seat, but it is not as much g-force as he should have experienced.

I also ask, how does David not splat into the walls of the spaceship because of inertia? The law of inertia says that an object will want to keep moving in a straight line until acted on by another force, therefore he should slam into ceiling when the spaceship comes to a stop in space. If you were driving at 70mph in your car with no seat belt and slammed into a wall, causing your car to stop, you would go flying out the windshield because of inertia. David's body will want to keep moving forward too, until he collides with the ceiling when the spaceship stops in space, and then the floor when the spaceship stops on earth. This leads me to the next question: how much force should David feel when he (should) slam into the walls of the spaceship when it stops? Will he survive the collision with the walls? There is no seat belt to stop him from flying around. Seat belts stop you from wanting to keep moving because of inertia. Because David has no seatbelt to stop him from flying around, he should experience the full reign of his force when colliding with the walls. I have estimated that David weighs about 50kg for the purpose of using the equation F=ma. Though it looks like the spaceship takes off and stops instantly, I will just assume that there is acceleration. Dividing 58.4km/second by 5.5 seconds leaves his acceleration at about 10km/second squared. David should experience 2.92x10^6N's of force when slamming into the ceiling and floor. It takes about 4,000N to break human bones, and this is more than enough force to crush a human flat.

This movie violates the law of inertia and pushes David well over the threshold of survivability. The force he experiences in terms of g and in splatting into the wall should leave him dead. Though this is a great classic movie, the directors totally neglected general laws of physics in this scene and much of the movie.

Sunday, November 10, 2019

Top Ten Bad Astronomy Examples vs The Martian

This is one of my favorite movies and have watched it many times. Philip Plait says there is a top ten bad astronomy examples in movies. Here I will put The Martian up against the top ten bad astronomy examples. 
  1. There were a few scenes in the movie where there were sounds coming from the Hermes spaceship in the movie. The most notable one, was when the Hermes was finally approaching earth. As Phillip Plait says, we are accustomed to the sounds of things passing by us. It makes since that the directors would put these sounds in for the watcher, but if you know that sound cannot be unless it has a medium to travel through, you may criticize the directors for not doing their space research.
  2. So there weren’t any scenes where one of the space ships had to avoid asteroids or other small dust particles. I’m glad there were no scenes like that because there is nothing but space and a Mars’ moon(which would easily have been avoided anyway).  
  3. Once again, there were not any scenes in The Martian where any spaceships were making hard turns(thumbs up). The spaceships were using Mars and the earth's gravity to turn around and accelerate, which is an accurate depiction of how it would go down in real life. 
  4. Here again we see no laser beams in The Martian. You generally see laser beams used in space battle, and there were no space battles in this movie. I like to think of this as shining a flashlight up into the night sky. You can’t see the beam, you would only see where the beam came in contact with something, like Philip Plait said “you only see the spot of light when it hits the wall”, but in this case the beam of light wouldn’t hit anything but air particles, and the light would just keep traveling. 
  5. There wasn’t any ridiculous space travel in The Martian, just a few trips to and from mars. The scenes where the Hermes crew was traveling back to earth I think were portrayed well because throughout the movie, they were on the Hermes. The directors didn’t make it seem like they were only traveling for a few days back to earth, and from earth. 
  6. There were no scenes about stealing water from the earth in this movie. No aliens and no need to steal our water anyway. 
  7. Again, no out of this universe gravitational laws in The Martian. There was no threat of getting “trapped” in a planet's gravity. They seemed to be well within the stable orbit range of earth and mars. 
  8. I think that this movie did pretty well in portraying distant stars. Whether orbiting mars or the earth, you will see the same stars in the same spots. A few million miles doesn’t measure up to 
  9. So there was only one explosion scene in The Martian and think they did a good job with the physics. The Hermes had to slow down so they could effectively catch Mark at a speed that was plausible. So what they did was placed a bomb on one of the hatches to blow off the door and release all the air. When the bomb when off, there was no fiery madness. All you saw was the door get blown off and the rush of air out the compartment. There should not be fire in space, because there is no oxygen to do so. 
  10. Lastly, there were no scenes where the moon was filmed with an inaccurate phase. 


Overall, I think the  directors did a pretty well directing this movie(minus the weightless scenes, they looked fake). The only really obvious thing about this movie that is an example of bad astronomy and physics is the spaceship sounds in space. I rate this movie PGP 13.

Sunday, November 3, 2019

Nuclear Weapons

I do not particularly think that we should be developing weapons of mass destruction. These weapons have the ability to wipe out an entire country when used consecutively, which I do not think is humane or moral to do so. I understand the need to out power other countries, for a place on the world stage, but at the same time I think each country should be equal in terms of nuclear power. If I were one of the scientists that developed the first two atomic bombs, I simply couldn’t live with myself. Civilians are not the problem when it comes to war. People who run the governments are the problem. If anyone should be ambushed in such a way it should the leaders of a country(if truly needed). I think that instead of developing these weapons that if the wrong person got ahold of could hurt thousands of people, maybe our government could just say we have many nuclear weapons so no one will risk messing with our country. After all, it's all about how much we say we have, because no other country really knows unless detected in tests. Maybe if weapons were developed for testing only, countries detect that we do have them. I think before building these weapons, the consequences of using them should be heavily taken into consideration.

Sunday, October 27, 2019

          I think most of the human population has a consensus that the earth is warming because of the ways we get energy, resources, and ultimately money. Ever since the first pieces of coal were burned, and the first cars were run on gas, we’ve been digging ourselves, and ecosystems, a pretty deep hole. There are many indicators of climate change. I think the most reliable evidence, for anything, is when data from before and after in present. So I think that the change in arctic sea ice is the most reliable. Not to mention, arctic sea ice does melt and refreeze with seasons, but the rate at which they are melting right now is not normal.

        Arctic sea ice reaches its minimum amount in September each year. March is when the maximum amount of ice is present. Every year the sea ice reaches September and March, the minimum and maximum amount of ice keeps getting smaller. NASA has a good video on this website: https://climate.nasa.gov/vital-signs/arctic-sea-ice/
You can see in the video in 2018, there was the least amount of ice. The conclusion from this data is the amount of ice, at maximum or minimum, is decreasing with each year. Not only is the air temperature at fault for this, but water temperature, and oceanic and atmospheric circulation can also be at fault(though not always a direct cause from global warming). Though this may not directly affect us because of where we live, it is a product of global warming and it will affect ecosystems and people who live in those areas. Many places rely on the water that melts out of sea ice, and the amount of water they can use gets smaller and smaller, especially when the ice melts early.

      
    I think this is the most reliable evidence of global warming because there is data from before and after. You cannot beat a before and after picture. I think that the global situation we have put ourselves in is really sad. Future generations will be affected by the environment because of our actions. Ecosystems will struggle to stay alive, and some will die. I really do wish big companies would stop rejecting these facts and start making changes, like reducing the amount of fossil fuels they extract and use. Obviously we can’t stop cold turkey, but at least prospective about new, greener technologies rather than obsessing over power and revenue.
https://www.epa.gov/climate-indicators/snow-ice


(I do not know why Blogger messes with the format of my blog. I cannot make the huge spaces go away, sorry for the inconvenience.)

Thursday, October 10, 2019

Gravity and the Normal Force


          For most people, when we think of gravity, we think of things like, weight, and pulling down. Though gravity does pull down, there is a misconception that gravity is what causes our weight on whatever surface, which is wrong. We actually perceive weight through the normal force.
   
         The normal force is perpendicular to whatever surface an object is in contact with(if you’re in mid air there is no normal force). Gravity pulls down, normal force pushes up, hence a surface supporting our weight. Another point is Newton’s 3rd law: for every reaction(gravity), there must be an equal and opposite reaction(normal force). If  there was no normal force to support our weight, we would fall through the ground until we reached the Earth's center of mass.
Image result for normal force picture      
            When solving for magnitude of the normal force, we use Newton's second law since it allows us to solve for a force. So, now you know that when there is a surface in contact with an object, the normal force is what supports that object. So what happens when someone is weightless? When there is an absence of gravity, why need a normal force to support you? In space, gravity is never completely absent(microgravity). You would have to be infinitely far from a mass in order for there to be absolutely no gravity. Astronauts in space feel weightless because they are in a constant free fall and there is no normal force. Remember I said in midair there is no normal force because there is no surface you’re in contact with? Weightlessness in space is that same concept. There is no ground to exert a normal force and the only force acting is gravity.
       
           So then why are the astronauts not literally falling toward the Earth? To successfully orbit the earth, you have to have the right velocity. If the velocity is too low, gravity will over power that velocity and pull you down to Earth. If the velocity is just right, there will be an equilibrium between the velocity and Earth’s gravity. The minimum orbit velocity for Earth is 17,000 mph.

          Another question one may find themselves asking about this concept is, can you only be in space to feel weightless? No! In order to feel weightless, there needs to be an absence of normal force, and you need to be in a free fall. At the fair, there are rides that bring you up really high then drop you. When you are in free fall, you are accelerating at -9.8 meters per second squared (acceleration of gravity). Whenever gravity is the only force acting upon you, you will feel weightless. Another example is in Apollo 13 the movie. The weightless space scenes were filmed in a free falling plane with only gravity pulling down. Once again, since gravity was the only force acting on them, they experienced weightlessness.

Image result for weightlessness

Friday, October 4, 2019

Newton and Infinity War


Image result for infinity war


So in superhero movies, it is normal that you see superhuman strength that disregards Newton's laws. But because of this being a physics class, we will be picky with our laws and how they are portrayed. 
Newton’s first law states that an object that is at rest, will want to stay at rest, and an object in motion will want to stay in motion and stay in the same direction and have the same speed(or not) until acted on by an external force. In this weeks movie, there is a scene where Hulk plummets into the atmosphere and crashes into Dr. Strange's house, and goes through his stairs, and eventually stops. The first law is shown in this scene when he digs into the stairs and eventually stopped by the ground. The only reason Hulk stopped was because the force of the ground against his fast moving body. If there would have been no ground to crash into, Hulk would have kept on moving, because the first law says that an object in motion, wants to stay in motion in the same direction and speed. 
Newton’s second law states that when a force is acted upon an object, there WILL be an acceleration(even if you can’t see it) and it will be inversely proportional to the object’s mass. There was a scene in the movie where Thor had to get these artificial rings around a dead neutron star moving so he could get a new axe. So what Thor did, was started swinging/accelerating the raccoon(he was at rest previously) so fast, that his interia (need to keep moving that fast) and energy in his momentum transferred to the rings. This would not be feasible because I know those rings weigh A LOT, a huge number, and that raccoon probably weighs only 15lbs. The point is, Thor acting on the raccoon who was at rest, resulted in an acceleration due to force, but how the scene went down(the rings started spinning) is not feasible. 

Newton’s third law says that for every reaction, there is an equal and opposite reaction. In Infinity War, the battle was for these stones that ruled the universe. One of the characters, Vision, has one of these stones, the mind stone, ingrained in his forehead, and Thanos is trying to steal it. So Thanos sends his allies to try and get this stone. In the scene, Vision was fighting a villain named Proxima Night. Proxima night has this gun stick thing that shoots out some sort of energy bullet(that is how it was portrayed). In this scene, Proxima Night is trying to take down Vision with her gun stick. Each time she shoots it, I noticed there is no recoil. There is no equal and opposite reaction for the amerture shooting out the gun stick. This is wrong because when Proxima Night missed Vision, it would break the object it hits, which concludes that there is a lot of energy needed to get the bullet moving that fast, and there should be recoil.


Image result for newton

Rating: PGP-13

Saturday, September 21, 2019

NASA's Blow Up an Asteroid Plan(More Studying to Conduct)

So, scarily and unfortunately, there are not too many plans NASA has
in the case of a NEO hitting the earth. I did happen to find a small
article on NASA’s website about possibly blowing up an asteroid
though, sort of like in the movie Armageddon. In the movie, the plan
they had in real life wouldn’t work. The asteroid was just too close,
moving too fast, and the machinery and tactics they were using were
just too risky. There would be a small chance of a plan like this
working. In the movie they even said they had never seen metal on
the asteroid like that before. So there was no telling what crazy
properties it could have had. 


In the abstract plan I found, it presents the idea of fragmenting an
asteroid using hyper velocity kinetic impactor with a subsurface
nuclear explosion in place. The article states that this could work if
the asteroid fragments as needed. If we were able to blow off parts of
the asteroid, there would be a better chance of our planet surviving
because the asteroid wouldn't have as much mass as before(and could
maybe slow it down). What scares me about this though, is launching
a nuclear bomb into space using huge amounts of rocket fuel. If the
rocket ship were to blow up in our atmosphere with a nuclear bomb in
it, the consequences could be very bad. 


Another very important part of this plan, is that we blow the asteroid up while it is 10 years out, not a few hundred miles from earth. Not only would this give us more time to blow up the asteroid, but if the asteroid is blown up and the fragments speeds escape the asteroids escape velocity, the likelihood of them hitting earth is low.


We have to remember that this plan is very far out. This is a phase one
study, or idea. There is much more studying and investigating to be
done. Phase two will seek out IDC (Integrated Design Center), and
NASA’s Goddard Space Center for more studying on this topic.
They will be looking to examine the technical feasibility, and the
overall effectiveness of this plan. 

In the meantime, I hope a NEO doesn’t hit the earth in my lifetime.
If so, I will gladly but uneasily watch as it plummets into our
atmosphere to kill us all. At the same time though, if a NEO is on its
way, I hope NASA comes up with more plans to stop it. 

Monday, September 16, 2019

Eraser

Image result for funny arnold schwarzenegger


This movie is a compilation of rail gun scenes, and every single scene is RP(retch physics). Whether a thug or buff Arnold is shooting the rail gun, there is first of all, no recoil whatsoever. Realistically, the recoil of a rail gun should blow off the top half of someone's body. Wouldn’t that be a great scene? On the other hand, when someone is shot by the rail gun, they are simply blown off their feet and hit the ground a few feet behind them. The conservation of momentum says that the momentum of the bullet should transfer to the target. So I did the math to see how much momentum the target man should have when hit by the bullet and this is what I found:





The target man should start moving at 1,113,514 meters per second when hit by the bullet. I don’t know exactly how much, but it takes an enormous amount of energy to get a 63 kilogram mass moving as 1,113,514 meters per second, especially all caused by a tiny little .26 gram bullet. Realistically, the target man should literally blow up so the energy of 1,113,514 meters per second has somewhere to go, other than getting the target man moving 1,113,514 meters per second which would be very, very hard. Only if the physics of the rail gun were real in this movie, because boy would that be a good movie.

Saturday, August 31, 2019

Mission Impossible 3

In Mission Impossible 3 I was able to pick out two scenes I think I can analyze. The first one I noticed was in the shootout at the abandoned warehouse. Tom Cruise used his last bullet to shoot a bad guy and totally blew him out the window. Is this possible? The bullet was portrayed as having a massive amount of kinetic energy. I have no idea what kind of gun Tom Cruise was using so I will assume it was an AK gun. Using the internet, I found that the bullet of an AK 47 travels at about 715 meters per second and weighs about 1.5 grams. The diameter of the bullet is about 8mm. Considering how small the surface area of the bullet is compared to the chest of the enemy, the bullet should've gone through him and made him drop to the ground. The enemy could have been thrown out the window if he was hit with something with a larger surface area, such as a bowling ball(especially going at the speed of an AK 47 round). There was also an affect where the enemy was lifted off the ground because of Tom Cruise's bullet. I can’t explain this. Just by watching this scene I know it is not accurate from a physics perspective. 


Another crazy scene in Mission Impossible 3, was when Tom Cruise ran a mile in 1 minute and
50 seconds. This took place in Shanghai. I rewatched the scene on Youtube and noted how long
he was running. After converting 1 minute and 50 seconds into hours(.03056 hours), I used
distance/time=speed to find his speed which came up at about 32mph(51 kilometers per hour).
This is faster than Usain Bolt, who runs at about 28mph. I highly doubt that Tom Cruise has
more talent than Usain Bolt. I could be wrong, but I am pretty set on it! 


Tom Cruise is without a doubt, extremely brave. The only way to retrieve the rabbit's foot was to
swing to the neighboring building, hundreds of feet tall. Since we don’t know the exact numbers
for relevant quantities, I will estimate. First, we need to know Toms potential energy, so we can t
hen calculate his kinetic energy when he jumps. He weighs 150lbs, or about 67 kilograms. Next
we need to know how far the buildings are apart, which I estimate are 200 feet(61 meters). The
length of the swinging cable, which has to be as long as the width between the two buildings, I
will also estimate is about 205 feet(62 meters). When Tom Cruise jumps off the building, he
should convert most of his potential energy into kinetic. Before the cable catches up with him,
he is free falling. One the cable does catch him, I think he loses a lot of the kinetic energy he had
before, hence slowing down his swing to the next building. Also, you have to acknowledge air
resistance. Because of this, I think that Tom wouldn’t have had enough kinetic energy to make
this swing up. 

MOVIE RATING: PGP-13